Roku (NASDAQ: ROKU) has made it clear that it's competing against some much bigger companies. It lists Apple (NASDAQ: AAPL), Alphabet's (NASDAQ: GOOG) (NASDAQ: GOOGL) Google, and Amazon (NASDAQ: AMZN) as some of its biggest competitors. All four companies make devices for streaming video on television sets, and that's one of Roku's main businesses.While Roku has shifted from making most of its money on its devices to primarily making money from selling premium subscriptions and video ads, it still needs people to use its devices to support the platform business.